Indirect Gas-Fired Make-Up Air Unit
An indoor space can receive clean air thanks to the modular indirect gas-fired heater (IGF). They can be installed indoors or outdoors and can run on either natural or LP gas. Combustion fumes won’t penetrate the fresh air stream thanks to the push-through architecture.
Since the burner is fired into a heat exchanger first, byproducts are contained within that isolated chamber and then exhausted through the flue. Therefore, a flame never directly comes in contact with fresh outside air that enters the space.

Table of Contents
We are the authorized distributors for the leading American manufacturers of indirect gas-fired make-up air units. We’ll be pleased to provide the ideal make up air unit for your application as authorized representatives.
For a fast quote or if you have inquiries about commercial or industrial MUA, get in touch with us.
Advantages of Indirect Gas-Fired Make-Up Unit
- Reheating - The ability to recirculate the tempered air in order to save energy
- No combustion byproducts enter the building
- Cooling & Heating MUA - Indirect burner can be placed downstream from a DX cooling module
- Ability to operate with less volume of air
Disadvantages
- Cost - Due to the addition of a heat exchange the equipment is more expensive than a direct-gas fired make-up air unit
- Efficiency - 75% - 80% range of efficiency translates into a higher operating cost
- Maintenance - Monitoring and maintaining the heat exchanger is required
- Equipment Size - Due to the heat exchanger the unit is larger than a direct gas-fired unit
- Temperature Control - Temperature cannot be precisely controlled
- Lower turndown ratios compared with DGF
IGF Features
- Stainless steel heat exchanger
- AMCA standard blowers
- Heavy gauge galvanized steel panels to withstand rust
- Vertically or horizontally mounting options
- Indoor or outdoor installation
- Perform above condensing temperature
- Combustion is properly ventilated regardless of indoor pressure
IDGF MUA are highly configurable and flexible. There are VAV options and recirculation features available that allow 100% outside air and constant volume.
Indirect Gas-Fired MUA Applications
When indoor air quality is a high priority then an IGF MUA is required. Other uses are when a direct gas fired unit is not approved for use.
Typical applications include, but not limited to:
- Chemical manufacturing facilities
- Pharmaceutical manufacturing facilities
- Clean rooms
- Laboratories
- Education Facilities
- Healthcare Industry
- Sports Industry
- Semiconductor Manufacturing (Foundries)
- Convention Centers
The American Gas Association and the Canadian Gas Association have certified and approved the type-409 stainless steel construction of all duct furnaces.
Direct Gas + DX-Cooling MUA Direct Gas-Fired + DX- Cooling Diagram Table of Contents Overview Authorized MUA Dealers We are the authorized distributors for the
Recirculating Make-Up Air Unit Recirculating Make-up Air Unit Diagram Table of Contents Overview Authorized MUA Dealers We are the authorized distributors for the leading American